Medication fluid infusion set component with integrated physiological analyte sensor, and corresponding fluid infusion device

ABSTRACT

Disclosed is a medical device component for delivering medication fluid to a patient. The medical device component includes a fluid infusion device to regulate delivery of medication fluid, a body-mountable base unit, and a top cover assembly that is removably couplable to the base unit and to the fluid infusion device. The base unit includes a cannula to deliver medication fluid under the control of the fluid infusion device, and a physiological analyte sensor to measure a physiological characteristic. The base unit also includes an electronics assembly electrically connected to sensor leads to obtain measurements in the analog domain, to convert measurements into digital sensor data, and to communicate conditioned digital sensor data to the fluid infusion device. The top cover assembly is configured to provide both fluid and electrical connections for the base unit, by way of an infusion tube having sensor conductors integrated therein or otherwise associated therewith.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/842,800, filed Dec. 14, 2017, which claims the benefit of U.S.provisional patent application No. 62/437,536, filed Dec. 21, 2016, andU.S. provisional application No. 62/503,282, filed May 8, 2017.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally tofluid infusion devices, such as medication infusion devices, insulinpumps, and the like. More particularly, embodiments of the subjectmatter relate to a medication fluid infusion set component having anintegrated sensor, and to a medication fluid infusion device thatincludes such an infusion set component.

BACKGROUND

Portable medical devices are useful for patients that have conditionsthat must be monitored on a continuous or frequent basis. For example,diabetics are usually required to modify and monitor their dailylifestyle to keep their blood glucose (BG) in balance. Individuals withType 1 diabetes and some individuals with Type 2 diabetes use insulin tocontrol their BG levels. To do so, diabetics routinely keep strictschedules, including ingesting timely nutritious meals, partaking inexercise, monitoring BG levels daily, and adjusting and administeringinsulin dosages accordingly.

The prior art includes a number of fluid infusion devices and insulinpump systems that are designed to deliver accurate and measured doses ofinsulin via infusion sets (an infusion set delivers the insulin througha small diameter tube that terminates at, e.g., a cannula inserted underthe patient's skin). In lieu of a syringe, the patient can simplyactivate the insulin pump to administer an insulin bolus as needed, forexample, in response to the patient's high BG level.

A typical fluid infusion pump includes a housing, which encloses a pumpdrive system, a fluid containment assembly, an electronics system, and apower supply. The pump drive system typically includes a small motor(DC, stepper, solenoid, or other varieties) and drive train componentssuch as gears, screws, and levers that convert rotational motor motionto a translational displacement of a stopper in a reservoir. The fluidcontainment assembly typically includes the reservoir with the stopper,tubing, and a catheter or infusion set to create a fluid path forcarrying medication from the reservoir to the body of a user. Theelectronics system regulates power from the power supply to the motor.The electronics system may include programmable controls to operate themotor continuously or at periodic intervals to obtain a closelycontrolled and accurate delivery of the medication over an extendedperiod.

The prior art also includes a variety of physiological analyte sensorsthat are designed to measure an analyte of a patient. For example,continuous glucose sensors employ subcutaneous glucose sensor technologythat facilitates ongoing monitoring of blood glucose levels. Continuousglucose sensors may utilize wireless data communication techniques totransmit data indicative of the blood glucose levels to a portableinfusion pump, a glucose monitor device, and/or other receiving devices.Thus, in a typical insulin pump system, the patient might wear both aninfusion set (for the delivery of insulin) and a glucosesensor-transmitter.

BRIEF SUMMARY

This disclosure relates to a medical device component for deliveringmedication fluid to a patient. Embodiments of the medical devicecomponent include a body-mountable base unit and a top cover assemblythat is removably couplable to the base unit. The base unit includes: abase structure; a body-insertable cannula coupled to the base structure,the cannula accommodating delivery of medication fluid to the patient; aself-sealing septum coupled to the base structure to fluidly seal an endof the cannula; a body-insertable physiological analyte sensor coupledto the base structure, the sensor facilitating measurement of aphysiological characteristic of the patient, and the sensor having aplurality of sensor leads; and an electronics assembly coupled to thebase structure. The electronics assembly is electrically connected tothe sensor leads to obtain measurements of the physiologicalcharacteristic in an analog domain. The electronics assembly includes adigital processing circuit to convert measurements of the physiologicalcharacteristic from the analog domain into digital sensor data, todigitally process the digital sensor data into conditioned digitalsensor data, and to communicate the conditioned digital sensor data to afluid infusion device associated with the medical device component. Thetop cover assembly includes: a lid structure that releasably mates withthe base structure, the lid structure having an interior space definedby an inner surface of the lid structure; an infusion tube coupled tothe inner surface of the lid structure and terminating within theinterior space; a tubing connector fluidly coupled to the infusion tube,the tubing connector having a distal end that penetrates theself-sealing septum to establish a fluid delivery flow path from theinfusion tube to the cannula when the top cover assembly is coupled tothe body-mountable base unit; a plurality of sensor conductors carriedby or integrated with the infusion tube, the sensor conductorsterminating within the interior space; and an electrical interconnectassembly coupled to the inner surface of the lid structure. Theelectrical interconnect assembly establishes electrical connectivitybetween the sensor conductors and the electronics assembly when the topcover assembly is coupled to the body-mountable base unit, to facilitatecommunication of the conditioned digital sensor data from theelectronics assembly to the fluid infusion device.

This disclosure also relates to a medical device component fordelivering medication fluid to a patient. Embodiments of the medicaldevice component include: a fluid infusion device to regulate deliveryof medication fluid; a base unit; and a top cover assembly that isremovably couplable to the base unit. The base unit includes: a cannulathat accommodates delivery of medication fluid as controlled by thefluid infusion device; a self-sealing septum that fluidly seals an endof the cannula; a physiological analyte sensor that facilitatesmeasurement of a physiological characteristic, the sensor having aplurality of sensor leads; and an electronics assembly electricallyconnected to the sensor leads to obtain measurements of thephysiological characteristic in an analog domain. The electronicsassembly includes a digital processing circuit to convert measurementsof the physiological characteristic from the analog domain into digitalsensor data, to digitally process the digital sensor data intoconditioned digital sensor data, and to communicate the conditioneddigital sensor data to the fluid infusion device. The top cover assemblyincludes: a lid structure that releasably mates with the base unit, thelid structure having an interior space defined by an inner surface ofthe lid structure; an infusion tube coupled to the inner surface of thelid structure and terminating within the interior space; a tubingconnector fluidly coupled to the infusion tube, the tubing connectorhaving a distal end that penetrates the self-sealing septum to establisha fluid delivery flow path from the infusion tube to the cannula whenthe top cover assembly is coupled to the base unit; a plurality ofsensor conductors terminating within the interior space; and anelectrical interconnect assembly coupled to the inner surface of the lidstructure. The electrical interconnect assembly establishes electricalconnectivity between the sensor conductors and the electronics assemblywhen the top cover assembly is coupled to the base unit, to facilitatecommunication of the conditioned digital sensor data from theelectronics assembly to the fluid infusion device.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the subject matter may be derived byreferring to the detailed description and claims when considered inconjunction with the following figures, wherein like reference numbersrefer to similar elements throughout the figures.

FIG. 1 is a plan view of an exemplary embodiment of a medical devicecomponent that includes a fluid infusion device;

FIG. 2 is a partially phantom perspective view of an exemplaryembodiment of an infusion tube having sensor conductors (in the form ofwires) integrated therein;

FIG. 3 is a partially phantom perspective view of another exemplaryembodiment of an infusion tube having sensor conductors (in the form ofwires) integrated therein;

FIG. 4 is a partially phantom perspective view of an exemplaryembodiment of an infusion tube having sensor conductors (in the form ofa ribbon cable) integrated therein;

FIG. 5 is a partially phantom perspective view of an exemplaryembodiment of an infusion tube having sensor conductors (in the form ofa flexible circuit arrangement) integrated therein;

FIG. 6 is a partially phantom perspective view of an exemplaryembodiment of an infusion tube having sensor conductors (in the form ofcrimped wires) integrated therein;

FIG. 7 is an end view of the infusion tube shown in FIG. 6 ;

FIG. 8 is a partially phantom perspective view of another exemplaryembodiment of an infusion tube having sensor conductors (in the form ofcrimped wires) integrated therein;

FIG. 9 is an exploded perspective view of an exemplary embodiment of acombined infusion-sensor unit suitable for use with the medical devicecomponent shown in FIG. 1 ;

FIG. 10 is a schematic block diagram that depicts certain features andelements of the combined infusion-sensor unit;

FIG. 11 is a perspective view of a portion of the combinedinfusion-sensor unit;

FIG. 12 is an exploded perspective view of a film connector of thecombined infusion-sensor unit;

FIG. 13 is a top view of a body-mountable base unit of the combinedinfusion-sensor unit;

FIG. 14 is a perspective cross-sectional view of the body-mountable baseunit, taken from line 14-14 of FIG. 13 ;

FIG. 15 is a cross-sectional view of a portion of the body-mountablebase unit, taken from line 15-15 of FIG. 13 ;

FIG. 16 is a top perspective view of the body-mountable base unit, witha protective cap installed thereon;

FIG. 17 is a bottom perspective view of a top cover assembly of thecombined infusion-sensor unit;

FIG. 18 is a perspective view of the top cover assembly, with a portionremoved to depict certain features;

FIGS. 19 and 20 are perspective cross-sectional views of the combinedinfusion-sensor unit;

FIG. 21 is a simplified block diagram schematic of an alternativeconnection scheme suitable for use with a combined sensor-infusion unit;

FIG. 22 is a partially phantom perspective view of an exemplaryembodiment of a base connector that provides both fluid and electricalconnections to a combined sensor-infusion unit;

FIGS. 23-29 are perspective views of various fluid/electrical connectionstructures suitable for use with a base connector of the type shown inFIG. 22 ;

FIG. 30 is a partially phantom end view of a portion of the connectionstructure depicted in FIG. 29 ;

FIG. 31 is a schematic representation of an exemplary embodiment of amodular sensor-infusion unit; and

FIG. 32 is a simplified block diagram of a connection scheme suitablefor use with a modular sensor-infusion unit.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description.

The subject matter described here relates to a fluid infusion device ofthe type used to treat a medical condition of a patient. The infusiondevice is used for infusing medication fluid into the body of a user.The non-limiting examples described below relate to a medical deviceused to treat diabetes (more specifically, an insulin pump), althoughembodiments of the disclosed subject matter are not so limited.Accordingly, the infused medication fluid is insulin in certainembodiments. In alternative embodiments, however, many other fluids maybe administered through infusion such as, but not limited to, diseasetreatments, drugs to treat pulmonary hypertension, iron chelation drugs,pain medications, anti-cancer treatments, medications, vitamins,hormones, or the like.

For the sake of brevity, conventional features and technologies relatedto infusion system operation, insulin pump and/or infusion setoperation, blood glucose sensing and monitoring, sensor signalprocessing, and other functional aspects of the fluid infusion system(and the individual operating components of the system) may not bedescribed in detail here. Examples of fluid infusion devices, analytesensors, and related components may be of the type described in, but notlimited to, U.S. Pat. Nos. 6,659,980; 6,892,085; and 7,621,893 (whichare incorporated by reference herein). Exemplary embodiments of aninfusion set component with integrated analyte sensor conductors aredisclosed in United States patent publication number 2012/0238849 (whichis incorporated by reference herein). An exemplary embodiment of a fluidinfusion device is disclosed in United States patent publication number2015/0314068 (which is incorporated by reference herein).

FIG. 1 is a schematic plan view of an exemplary embodiment of a medicaldevice component 100. The medical device component 100 includes twoprimary elements: a fluid infusion device 102 (e.g., an insulin pump)and an infusion set component 104, which can be coupled to the fluidinfusion device 102 as depicted in FIG. 1 . This particular embodimentof the infusion set component 104 includes, without limitation: aninfusion tube 110; a medical device component realized in the form of acombined infusion-sensor unit 112 coupled to one end 114 of the infusiontube 110; and a connector assembly 116 coupled to the other end 118 ofthe infusion tube 110. The fluid infusion device 102 is designed to becarried or worn by the patient, and the infusion set component 104terminates at the combined infusion-sensor unit 112 such that the fluidinfusion device 102 can deliver medication fluid to the body of thepatient in a controlled and regulated manner via the infusion tube 110.Moreover, the combined infusion-sensor unit 112 cooperates with thefluid infusion device 102 to sense, measure, or detect an analyte of thepatient (such as blood glucose), as described in more detail below. Thefluid infusion device 102 may leverage a number of conventionalfeatures, components, elements, and characteristics of existing fluidinfusion devices. For example, the fluid infusion device 102 mayincorporate some of the features, components, elements, and/orcharacteristics described in U.S. Pat. No. 7,621,893 and United Statespatent publication number 2015/0314068, the relevant content of which isincorporated by reference herein.

The fluid infusion device 102 operates to regulate the delivery ofmedication fluid to the patient. The fluid infusion device 102 generallyincludes an electronics and power module 122 that controls a mechanism(not shown) to actuate a fluid reservoir 124 housed in the body of thefluid infusion device 102. When realized as an insulin infusion pump,the fluid infusion device 102 controls and manages the delivery ofinsulin to manage blood glucose levels of the patient. The fluidinfusion device 102 accommodates the fluid reservoir 124 that containsthe medication fluid to be delivered to the user. The infusion tube 110represents the fluid flow path that couples the fluid reservoir 124 tothe combined infusion-sensor unit 112. When installed as depicted inFIG. 1 , the infusion tube 110 extends from the fluid infusion device102 to the combined infusion-sensor unit 112, which in turn provides afluid pathway to the body of the patient. For the illustratedembodiment, the connector assembly 116 is realized as a removablereservoir cap (or fitting) that is suitably sized and configured toaccommodate replacement of fluid reservoirs 124 (which are typicallydisposable) as needed. In this regard, the reservoir cap is designed toaccommodate the fluid path from the fluid reservoir 124 to the infusiontube 110. Accordingly, the fluid reservoir 124 is fluidly coupled to theinfusion tube 110, by way of the connector assembly 116.

In certain implementations, a number of sensor conductors are carriedby, integrated with, or are otherwise provided by the infusion tube 110.In this regard, the infusion tube 110 can be fabricated with electricalsensor conductors embedded therein to support the operation of abody-insertable physiological analyte sensor located at the combinedinfusion-sensor unit 112. In accordance with the embodiments presentedhere, the sensor conductors are suitably configured and arranged toprovide operating power from the fluid infusion device 102 to thecombined infusion-sensor unit 112. In addition, the sensor conductorsare suitably configured and arranged to transmit digital data from thecombined infusion-sensor unit 112 to the fluid infusion device 102. Inthis regard, the infusion tube 110 performs at least three primaryfunctions during normal operation of the fluid infusion device 102: (1)deliver medication fluid to the patient; (2) provide operating voltageto the combined infusion-sensor unit 112; and (3) convey digital data(e.g., digital sensor data obtained from the analyte sensor of thecombined infusion-sensor unit 112) to the fluid infusion device 102.

In practice, the electronics and power module 122 of the fluid infusiondevice 102 may be used to generate voltage, current, and/or electricalsignals for use by the combined infusion-sensor unit 112 as needed, andthe electronics and power module 122 may also be used to detect orreceive digital data that represents the measured analyte of thepatient. In this regard, the electronics and power module 122 iselectrically connected to contacts or terminals of the connectorassembly 116, wherein the contacts or terminals correspond to the sensorconductors of the infusion tube 110.

FIGS. 2-8 show various infusion tube embodiments, each having sensorconductors integrated therein. More specifically: FIG. 2 is a partiallyphantom perspective view of an exemplary embodiment of an infusion tubehaving sensor conductors (in the form of wires) integrated therein; FIG.3 is a partially phantom perspective view of another exemplaryembodiment of an infusion tube having sensor conductors (in the form ofwires) integrated therein; FIG. 4 is a partially phantom perspectiveview of an exemplary embodiment of an infusion tube having sensorconductors (in the form of a ribbon cable) integrated therein; FIG. 5 isa partially phantom perspective view of an exemplary embodiment of aninfusion tube having sensor conductors (in the form of a flexiblecircuit arrangement) integrated therein; FIG. 6 is a partially phantomperspective view of an exemplary embodiment of an infusion tube havingsensor conductors (in the form of crimped wires) integrated therein;FIG. 7 is an end view of the infusion tube shown in FIG. 6 ; and FIG. 8is a partially phantom perspective view of another exemplary embodimentof an infusion tube having sensor conductors (in the form of crimpedwires) integrated therein. It should be appreciated that FIGS. 2-8depict a number of suitable implementations of the infusion tube 110 ina non-limiting and non-exhaustive manner. An embodiment of the infusionset component 104 can incorporate an infusion tube 110 having adifferent configuration and/or arrangement of sensor conductors if sodesired.

In general, the infusion tube 110 is fabricated with electrical sensorconductors integrated therein or carried thereon to support theoperation of the sensor located at the combined infusion-sensor unit112. The infusion tube 110 is formed from an appropriate type andcomposition of tubing material, which is fabricated with an interiorfluid canal defined therein. The interior fluid canal provides a fluidpathway for the medication fluid. The tubing material may be anyflexible, tough, and lightweight material such as, without limitation: apolyethylene polymer; a polyurethane polymer; or the like. For theexemplary embodiment described here, the tubing material is a molded orextruded concentric construction, which may include multiple concentriclayers or a single layer. Moreover, the infusion tube 110 is formed froma material (or materials) that is compatible with the particular type ofmedication fluid or fluids to be delivered, such as insulin medicationfluid.

The infusion tube 202 depicted in FIG. 2 includes three sensorconductors 204 wrapped around an inner tubing layer 206 (althoughalternate embodiments may include more or less than three sensorconductors). For this particular embodiment, the three sensor conductors204 are utilized as a power conductor, a ground conductor, and a dataconductor. Accordingly, the sensor conductors 204 provide operatingpower to the combined infusion-sensor unit 112, and also accommodate thetransmission of digital data (representing the analyte sensormeasurements) from the combined infusion-sensor unit 112 to the fluidinfusion device 102. Notably, the sensor conductors 204 are not intendedto convey analog sensor information because the combined infusion-sensorunit 112 performs analog-to-digital conversion of the analog sensorvalues, performs digital data conditioning on the converted digitaldata, and sends the conditioned sensor data to the fluid infusion device102 in the digital domain.

The sensor conductors 204 may be realized as thin cooper wires, metaltraces, or conductive filaments. An outer tubing layer 208 of theinfusion tube 202 surrounds and insulates the sensor conductors 204.Alternatively, the sensor conductors 204 can be embedded in a layer ofthe tubing material. In this regard, the tubing material may be composedof an electrically insulating material to electrically insulate each ofthe sensor conductors. In such an embodiment, the sensor conductors neednot be individually surrounded by an insulating sleeve or casing. Inpractice, the sensor conductors could be molded within the tubingmaterial such that they are spaced apart from one another as shown inFIG. 2 . In other embodiments, insulated sensor conductors (e.g., wirescovered in an insulating material) can be wrapped overlying theoutermost surface of the infusion tube 202. Such an arrangement can havemanufacturing and/or assembly advantages related to establishingelectrical connections for the wires.

The infusion tube 212 shown in FIG. 3 is similar to the infusion tube202 depicted in FIG. 2 , however, the three sensor conductors 214 arewrapped around (and embedded within) the outer tubing layer 216. Theinfusion tube 212 also includes a concentric inner tubing layer 218surrounded by the outer tubing layer 216 and, therefore, surrounded bythe sensor conductors 214.

The infusion tube 222 shown in FIG. 4 includes sensor conductors thatare realized in the form of a ribbon cable 224. For this example, theribbon cable 224 includes three adjacent conductors, grouped togetherbut electrically insulated from each other. FIG. 4 depicts the ribboncable 224 wrapped around a tubing layer 226. In practice, the ribboncable 224 can serve as the outermost layer of the infusion tube 222 dueto its self-insulated nature. Alternatively, the infusion tube 222 caninclude an outer tubing layer (not shown) that is formed overlying theribbon cable 224.

The infusion tube 232 shown in FIG. 5 includes sensor conductors thatare realized in the form of a flexible circuit arrangement 234. Inaccordance with the illustrated embodiment, the flexible circuitarrangement 234 has a bent “wave” shape that allows a relatively flatcircuit design to stretch and move easily when the infusion tube 232 isbent. The flexible circuit arrangement 234 is arranged in a flatorientation, and it can be embedded in the inner tubing layer 236,embedded in the outer tubing layer 238 (as shown), or positioned betweenthe inner and outer tubing layers 236, 238.

The infusion tube 242 shown in FIG. 6 and FIG. 7 includes sensorconductors that are realized in the form of crimped wires 244 thatterminate in relatively straight ends. The crimped wires 244 can easilystretch and compress to accommodate bending of the infusion tube 242. Inaccordance with the illustrated embodiment, the crimped wires 244 arearranged side by side, and they can be embedded in the inner tubinglayer 246, embedded in the outer tubing layer 248, or positioned betweenthe inner and outer tubing layers 246, 248. Notably, the straight andrelatively flat layout of the ends of the crimped wires 244 (see FIG. 7) makes it easy to physically and electrically connect the crimped wires244 to a circuit board, an interconnect assembly, contact pads, or thelike.

The infusion tube 252 depicted in FIG. 8 also includes sensor conductorsimplemented in the form of crimped wires 254. The infusion tube 252 issimilar to the infusion tube 242 shown in FIG. 7 . The illustratedembodiment of the infusion tube 252, however, includes a spaced-apartarrangement of the crimped wires 254. For example, the crimped wires 254can be oriented 120 degrees apart to balance the mass of the infusiontube 252. The crimped wires 254 can be embedded in the inner tubinglayer 256, embedded in the outer tubing layer 258, or positioned betweenthe inner and outer tubing layers 256, 258.

FIG. 1 depicts the combined infusion-sensor unit 112 in a simplifiedschematic form. An exemplary embodiment of the infusion-sensor unit 112will now be described with reference to FIGS. 9-20 . It should beappreciated that these figures merely depict one possibleimplementation, and that alternative embodiments of the infusion-sensorunit 112 can be realized if so desired. FIGS. 9-20 illustrate anembodiment of the infusion-sensor unit 112 that includes two primarysubcomponents: a body-mountable base unit 302; and a top cover assembly304 that is removably couplable to the base unit 302. The base unit 302is designed to be affixed to the skin of the patient and worn in thatmanner for a designated period of time, e.g., up to several days, aweek, or the like. An appropriate insertion/installation mechanism canbe used to mount the base unit 302 onto the skin and to deploy insertionneedles to insert the infusion cannula and the analyte sensor into theskin. The top cover assembly 304 mates with, and is secured to, the baseunit 302 in a way that establishes the necessary mechanical, electrical,and fluid connections (as described in more detail below).

FIG. 9 is an exploded perspective view of the infusion-sensor unit 112,and FIG. 10 is a schematic block diagram that depicts certain featuresand elements of the infusion-sensor unit 112. FIG. 11 is a perspectiveview of a portion of the infusion-sensor unit 112, and FIG. 12 is anexploded perspective view of a film connector suitable for use on acircuit board of the infusion-sensor unit 112. FIG. 13 is a top view ofthe base unit 302, FIG. 14 is a perspective cross-sectional view of thebase unit 302, taken from line 14-14 of FIG. 13 , and FIG. 15 is across-sectional view of a portion of base unit 302, taken from line15-15 of FIG. 13 . FIG. 16 is a top perspective view of the base unit302, with a protective cap installed thereon, FIG. 17 is a bottomperspective view of the top cover assembly 304, and FIG. 18 is a bottomperspective view of a portion of the top cover assembly 304. FIGS. 19and 20 are perspective cross-sectional views of the combinedinfusion-sensor unit 112.

The base unit 302 includes a base structure 306 and a lid assembly 308,which is affixed and sealed to the base structure 306. The lid assembly308 is not intended to be removed from the base structure 306—the lidassembly 308 protects the components carried by the base structure 306from the ingress of water, fluid, dust, dirt, and other potentialcontaminants. The base structure 306 includes or cooperates with theprimary devices, components, and elements of the infusion-sensor unit112. For this particular embodiment, the base unit 302 includes at leastthe following items, without limitation: a circuit board 310; abody-insertable cannula 312 coupled to the base structure 306, whereinthe cannula 312 accommodates the delivery of medication fluid to thepatient; a self-sealing septum 314 coupled to the base structure 306 andconfigured to fluidly seal the upstream end of the cannula 312; abody-insertable physiological analyte sensor 316 coupled to the basestructure 306, wherein the sensor 316 facilitates the measurement of aphysiological characteristic of the patient (such as blood glucose); andan electronics assembly 318 coupled to the base structure 306 andimplemented on the circuit board 310. The electronics assembly 318 isschematically depicted in FIG. 10 , and various unlabeled electroniccomponents and devices of the electronics assembly 318 are shown inFIGS. 9, 11, 12, 14, 19, and 20 .

The base structure 306 may include a rigid housing or platform 320 thatis designed and configured to support the various components of the baseunit 302. The platform 320 may, for example, be fabricated from a moldedor machined plastic material or any appropriate material. The circuitboard 310 is mounted to the platform 320, which also includes structuralfeatures for mounting and securing the cannula 312, the septum 314, thesensor 316, etc. As shown in FIG. 14 and FIG. 19 , the septum 314 ismaintained in position between the base structure 306 and the lidassembly 308 such that it can seal the upstream end of the cannula 312when the top cover assembly 304 is removed from the base unit 302. Thetop end of the septum 314 is accessible via a hole 322 formed in the topsurface 324 of the lid assembly 308 (which corresponds to the topsurface of the base unit 302). Also shown in FIG. 14 and FIG. 19 isanother septum 326 that seals another hole 328 formed in the top surface324. As explained in more detail below, the septum 326 seals the hole328 after insertion of the sensor 316.

Referring to the block diagram of FIG. 10 , the base structure 306includes the following items, without limitation: the electronicsassembly 318; a film connector 332 electrically coupled to the sensorleads of the sensor 316; an interconnect structure 334; conductive pads336 arranged and configured to contact corresponding interconnectionplugs of the lid assembly 308; and at least one battery 338 (or othertype of power supply). The film connector 332 is also shown in FIG. 11and FIG. 12 . The conductive pads 336 are also shown in FIG. 20 (in across-sectional view). In practice, the electronics assembly 318 iscoupled to the base structure 306 (by way of the circuit board 310), andthe electronics assembly 318 is electrically connected to the sensorleads to obtain measurements of the physiological characteristic in ananalog domain. The electronics assembly 318 includes a digitalprocessing circuit and/or suitable digital processing logic to convertmeasurements of the physiological characteristic from the analog domaininto digital sensor data, to digitally process the digital sensor datainto conditioned digital sensor data, and to communicate the conditioneddigital sensor data to the fluid infusion device 102, which isassociated with or connected to the infusion-sensor unit 112. Inaccordance with certain embodiments, the electronics assembly 318includes at least the following items, without limitation: a smallrechargeable battery that supports data collection and sensor powerduring brief periods when the top cover assembly is disconnected; amemory device, chip, or element that stores measurement data (which maybe collected during disconnect periods) for later data retrieval; sensoranalog front end discrete components with the possibility of supportingan electro impedance spectroscopy diagnostic and/or other forms ofsensor diagnostics; a low power microprocessor device that isresponsible for the required processing intelligence and logic (e.g.,data communication, commanding the analog front end circuit, digitaldata processing).

Referring to FIG. 10 , FIG. 11 , and FIG. 12 , the exemplary glucosesensor embodiment presented here employs a sensor 316 having threesensor leads 344. The sensor leads 344 include a reference conductor fora reference electrode of the sensor 316, a working conductor for aworking electrode of the sensor 316, and a counter conductor for acounter electrode of the sensor 316. The sensor leads 344 provide analogsignal values to the electronics assembly 318, by way of the filmconnector 332 and the interconnect structure 334, which can be realizedwith conductive traces, lines, or elements of the circuit board 310. Inthis regard, FIG. 12 depicts an exemplary implementation that includes apiece of adhesive 345 for affixing the end of the sensor 316 to thecircuit board 310, and that includes conductive traces 346 or pads thatform a part of the interconnect structure 334. The film connector 332electrically couples the sensor leads 344 to the conductive traces 346,which in turn are electrically coupled to the electronics assembly 318,the battery 338, and the conductive pads 336 (refer to FIG. 10 ).

The illustrated embodiment has three conductive pads 336, which areassigned to a power conductor, a ground conductor, and a data conductorfor communication of conditioned digital sensor data from theelectronics assembly 318 to the fluid infusion device 102. Theseconductive pads 336 are also utilized to provide operating power fromthe fluid infusion device 102 to the electronics assembly 318 when thetop cover assembly 304 is coupled to the base unit 302. The battery 338provides “backup” operating power to the electronics assembly 318 whenthe top cover assembly 304 is removed from the base unit 302.

The lid assembly 308 of the base unit 302 will now be described withparticular reference to FIGS. 9 and 13-20 . The lid assembly 308 may,for example, be fabricated from a molded or machined plastic material orany appropriate material, as a unitary one-piece construction or as anassembly of different parts. As mentioned above, the illustratedembodiment of the lid assembly 308 includes the top surface 324 and theholes 322, 328 that extend to the top surface 324. The illustratedembodiment of the lid assembly 308 also includes a suitably configuredconnector structure 350 that is used to convey the digital datagenerated by the base unit 302, and to provide operating voltage to thebase unit 302 from the host fluid infusion device.

The illustrated embodiment of the connector structure 350 includes apedestal 352 extending from the base unit 302 and interconnection plugs354 positioned within the pedestal 352. The pedestal 352 can beintegrally formed with the remaining material of the lid assembly 308.The interconnection plugs 354 are electrically conductive elements thatestablish electrical connections between the electronics of the baseunit 302 and corresponding electrical contacts of the top cover assembly304 (when the top cover assembly 304 is attached to the base unit 302).For this particular embodiment, the interconnection plugs 354 are formedfrom a conductive elastomeric material, which is desirable to establishgood and reliable electrical contacts. The pedestal 352 includes throughholes formed therein to receive and retain the interconnection plugs354.

The lower ends of the interconnection plugs 354 are electrically coupledto the corresponding conductive pads 336 of the electronics assembly 318in the base unit 302 (as mentioned previously; see FIG. 20 ). When thetop cover assembly 304 is coupled to the base unit 302, the upper endsof the interconnection plugs 354 mate with, and physically contact,corresponding electrical contact pads of an electrical interconnectassembly mounted inside the top cover assembly 304 (as described in moredetail below). Thus, the interconnection plugs 354 are designed tophysically and electrically couple the conductive pads 336 to theelectrical interconnect assembly of the top cover assembly 304. Asmentioned above, the interconnection plugs 354 correspond to a powerconductor, a ground conductor, and a data conductor for communication ofthe conditioned digital sensor data.

Referring to FIG. 16 , the medical device component 100 may also includea protective cap 358 for the connector structure 350. The protective cap358 is shaped, sized, and configured to mate with and seal the connectorstructure 350 when the top cover assembly 304 is removed from the baseunit 302. The protective cap 358 prevents electrical shorting of theinterconnection plugs 354 and minimizes contamination and damage to theconnector structure 350.

The top cover assembly 304 will now be described with particularreference to FIGS. 9 and 17-20 . The top cover assembly 304 is designedand configured to be installed onto and removed from the base unit 302as needed. In certain embodiments, the top cover assembly 304 and thebase unit 302 are cooperatively and compatibly designed with certainfeatures to enable the top cover assembly 304 to be secured onto thebase unit 302. During normal operation of the infusion system, the topcover assembly 304 is affixed to the base unit 302 to establish andmaintain both fluid connections and electrical connections between thetop cover assembly 304 and the base unit 302. As explained previously,an infusion tube provides the fluid and electrical connections betweenthe top cover assembly 304 and the attached fluid infusion device. Thepatient or a caregiver can temporarily remove the top cover assembly 304from the base unit 302 for various reasons, e.g., bathing, showering,swimming, replacement of the infusion set, maintenance of the infusionset or the infusion device, cleaning, or the like.

The top cover assembly 304 generally includes, without limitation: a lidstructure 360; an infusion tube 362 (which carries the sensor conductorsor has the sensor conductors integrated therein, as described above); atubing connector 364; and an electrical interconnect assembly 366. Theseprimary elements will be described in more detail below.

The lid structure 360 may, for example, be fabricated from a molded ormachined plastic material or any appropriate material, as a unitaryone-piece construction or as an assembly of different parts. For thisparticular embodiment, the lid structure 360 is designed and configuredto releasably mate with the base structure 306 of the base unit 302. Tothis end, the lid structure 360 and the base structure 306 can includesnap-fitting features, clips, tabs, buttons, dimensions to accommodate apress-fit or pressure-fit engagement, slots and keys, etc. In thisregard, FIG. 17 and FIG. 19 depict two tabs 368 of the lid structure 360that engage and cooperate with corresponding slots, tabs, or shouldersof the base structure 306. The lid structure 360 resembles a shellhaving an interior space 370 that is defined by an inner surface 372 ofthe lid structure 360 (see FIG. 17 ).

The infusion tube 362 represents one exemplary embodiment of theinfusion tube 110 described above. The infusion tube 362 is coupled to(or near) the inner surface 372 of the lid structure 360 such that anend of the tube 362 terminates within the interior space 370. For theillustrated embodiment, the lid structure 360 includes at least onestructural feature 376 that receives, secures, and retains the end ofthe tube 362. FIG. 18 depicts the structural feature 376 incross-section, i.e., with a portion of it removed. As shown in FIG. 17and FIG. 18 , the end of the infusion tube 362 is exposed to allow thesensor conductors 378 to extend from the infusion tube 362. Accordingly,the sensor conductors 378 terminate within the interior space 370 of thelid structure 360. Thus, the terminating end of each sensor conductor378 extends from the end of the infusion tube 362 and is exposed forconnection to the electrical interconnect assembly 366.

The tubing connector 364 is shown in FIGS. 17-19 . The tubing connector364 is fluidly coupled to the infusion tube 362 such that it diverts thefluid flow path from inside the infusion tube 362. For this particularembodiment, the downstream end 380 of the tubing connector 364 residesinside the infusion tube 362 and forms a seal with the interior surfaceof the infusion tube 362 to inhibit leakage of fluid around the outersurface of the tubing connector 364. In this regard, the tubingconnector 364 is preferably fabricated from a rigid material (e.g., hardplastic or stainless steel) that can be press fit inside the infusiontube 362. As shown in FIG. 18 , the tubing connector 364 can beintroduced into the infusion tube 362 through a slot 382 or otheropening in the wall of the infusion tube 362.

The distal (downstream) end 384 of the tubing connector 364 is supportedby the structural feature 376 of the lid structure 360 (see FIG. 17 ).The distal end 384 of the tubing connector 364 is rigid and somewhatpointed such that it can easily penetrate the self-sealing septum 314 ofthe base structure 306 to establish a fluid delivery flow path frominside the infusion tube 362 to the cannula 312 when the top coverassembly 304 is coupled to the base unit 302 (see FIG. 19 ). Thus, whenthe top cover assembly 304 is properly installed onto the base unit 302,the tubing connector directs flow of the medication fluid from insidethe infusion tube 362, through the septum 314, and into the cannula 312,which in turn delivers the medication fluid to the body of the patient.

The electrical interconnect assembly 366 of the top cover assembly 304is best shown in FIG. 17 and FIG. 18 . A portion of the electricalinterconnect assembly 366 is also shown in the cross-sectional views ofFIG. 19 and FIG. 20 . The interconnect assembly 366 can be implementedas a printed circuit board that is fabricated using known techniques andmethodologies. The interconnect assembly 366 is physically coupled tothe inner surface 372 of the lid structure 360 in the desired location.For this particular embodiment, the interconnect assembly 366 is apassive component having electrically conductive traces, plugs, contactpads, and/or other elements that are arranged to electrically connectthe sensor conductors 378 to the interconnection plugs 354 of the baseunit 302. Accordingly, when the top cover assembly 304 is coupled to thebase unit 302, the electrical interconnect assembly 366 establisheselectrical connectivity between the sensor conductors 378 and theelectronics assembly 318 of the base unit 302, which facilitatescommunication of the conditioned digital sensor data from theelectronics assembly 318 to the fluid infusion device. In addition, theelectrical interconnect assembly 366 allows the fluid infusion device toprovide operating power (voltage) to the base unit 302 as needed.

As shown in FIG. 17 and FIG. 18 , the sensor conductors 378 can bebonded, soldered, press-fit, force-fit, or otherwise coupled tocorresponding contacts formed on an exposed surface 390 of theinterconnect assembly 366. The interconnect assembly 366 includes threeelectrical contact pads 392—one for each of the sensor conductors 378.The interconnect assembly 366 also includes three conductive paths(hidden from view) that connect the contact pads 392 to the contactsassigned to the respective sensor conductors 378. The shape, size,layout, and arrangement of the contact pads 392 are compatible with thearrangement of interconnection plugs 354 (see FIG. 20 ). When the topcover assembly 304 is installed on the base unit 302, the contact pads392 are forced into physical and electrical contact with the upper endsof the interconnection plugs 354.

Referring again to FIGS. 9, 13, 14, and 16-19 , the hole 322 formed inthe top surface 324 of the base unit 302 accommodates insertion andwithdrawal of the tubing connector 364 (during installation and removalof the top cover assembly 304), and also accommodates an insertionneedle used to insert the cannula 312 into the skin of the patient whenthe base unit 302 is initially deployed. FIG. 14 shows the base unit 302without the tubing connector 364, and FIG. 19 shows the base unit 302with the tubing connector 364 installed through the hole 322 and intothe septum 314. The other hole 328 formed in the top surface 324 of thebase unit 302 accommodates another insertion needle that is used toinsert the physiological analyte sensor 316 into the skin of the patientwhen the base unit 302 is initially deployed. After the base unit 302has been deployed, the hole 324 remains plugged by the septum 326.

Alternative Connection Schemes

The exemplary embodiment described above utilizes the top cover assembly304 as a mechanism for establishing the fluid and electrical connectionsto the base unit 302. In practice, any suitably configured connectionmethodology or scheme can be employed with a combined sensor-infusionunit of the type described herein. In this regard, FIG. 21 is asimplified block diagram schematic of an alternative connection schemesuitable for use with a combined sensor-infusion unit 400 of the typegenerally described above. This description assumes that thesensor-infusion unit 400 includes a sensor electronics assembly 402, aninterconnect 404 formed of an electrically conductive elastomer, and aself-sealing septum 406. The interconnect 404 is electrically coupled toone or more contact pads of the sensor electronics assembly 402.

The sensor-infusion unit 400 is compatible with a base connector 410,which is attached to an infusion tube 412 having embedded or integratedsensor conductors 414 (depicted as a single line in FIG. 21 ). Forsimplicity and ease of illustration, FIG. 21 does not show the fluidflow path for the medication fluid carried by the infusion tube 412.Nonetheless, it should be appreciated that the medication fluid isdelivered to the patient via the infusion tube 412, through a fluidconduit or path formed in the base connector 410, and through acorresponding fluid conduit or path formed in the sensor-infusion unit400.

The sensor conductors 414 are electrically coupled to thesensor-infusion unit 400 by way of an electrical connector 416, whichincludes connection pins 418 for the sensor conductors 414. FIG. 21 onlyshows one connection pin 418, which penetrates the septum 406 toestablish an electrical contact with the interconnect 404 (as shown inFIG. 21 ). The electrical connection between the base connector 410 andthe sensor-infusion unit 400 is waterproof (or water resistant by atleast a specified amount). The septum 406 is self-sealing to create awatertight seal when the base connector 410 is removed from thesensor-infusion unit 400.

The manner in which the sensor conductors 414 are terminated from theinfusion tube 412 to the base connector 410 can vary from one embodimentto another. In this regard, any of the following techniques can beleveraged, without limitation: soldering wires to a circuit board or aconductive pin; mechanical pin connections; hot bar bonding or solderingwires to solder pads of a circuit board; connecting wires to aconductive elastomer; pressing or forcing wires into a cutter element tomake electrical connections; forcing a cutter element into the infusiontube 412 to make electrical connections with the sensor conductors 414;etc.

FIG. 22 is a partially phantom perspective view of an exemplaryembodiment of a base connector 422 that provides both fluid andelectrical connections to a combined sensor-infusion unit (not shown).The depicted base connector 422 leverages a legacy configuration that iscompatible with currently available glucose sensor packages. The legacyconfiguration has been modified to enable the base connector 422 toestablish the required number of electrical connections (e.g., three forthe exemplary embodiment presented here). The base connector 422includes a generally c-shaped body 424 that is designed to mechanicallyattach to the sensor-infusion unit. The body 424 is configured toreceive an infusion tube 426 that carries three sensor conductors(partially obscured from view in FIG. 22 ). The base connector 422 alsoincludes an interface component 428 that serves as a fluid transitionfrom the infusion tube 426 to an infusion needle 430, and as anelectrical transition from the sensor conductors to three correspondingconnector pins 432. The infusion needle 430 and the connector pins 432mate with, and couple to, respective elements of the sensor-infusionunit.

FIG. 23 is a perspective view of a fluid/electrical connection structure450 suitable for use with the base connector 422. The connectionstructure 450 includes a coupling element 452 that couples the infusiontube 426 to an interface component 454, which can be implemented as aprinted circuit board. An infusion needle 456 protrudes from a seal,plug, or septum in the front of the interface component 454. Threeconnector pins 458 extend from the front of the interface component 454.The three sensor conductors 460 also extend from the seal, plug, orseptum, and each conductor 460 is soldered, welded, or otherwiseelectrically connected to a respective electrical junction point on theinterface component 454. Each electrical junction point is connected toone of the connector pins 458.

FIG. 24 is a perspective view of another fluid/electrical connectionstructure 466 that is suitable for use with the base connector 422. Theconnection structure 466 is similar to the connection structure 450shown in FIG. 23 , and similar or identical features and elements willnot be redundantly described here. In contrast to that described abovefor the connection structure 450, the sensor conductors 468 of theconnection structure 466 are attached directly to the connector pins 470(rather than to the interface component 472). For this arrangement, theinterface component 472 is fabricated from a nonconductive material,such as plastic.

FIG. 25 is a perspective view of another fluid/electrical connectionstructure 476 that is suitable for use with the base connector 422. Theconnection structure 476 is similar to the connection structure 450shown in FIG. 23 , and similar or identical features and elements willnot be redundantly described here. For this embodiment, the sensorconductors 478 extend from the infusion tube in alignment with theinterface component 480, and are bonded to conductive pads 482 bytraditional soldering or hot bar soldering for ease of manufacturing.

FIG. 26 is a perspective view of another fluid/electrical connectionstructure 486 that is suitable for use with the base connector 422. Theconnection structure 486 is similar to the other connection structuresmentioned previously, and similar or identical features and elementswill not be redundantly described here. For this embodiment, the sensorconductors extend from the infusion tube and are terminated inconductive elastomer plugs 488 located in the interface component 490.The conductive elastomer plugs 488 are connected to an interconnect orcircuit arrangement of the interface component 490 (not shown in FIG. 26), which in turn is electrically coupled to certain features of thesensor-infusion unit.

FIG. 27 is a perspective view of another fluid/electrical connectionstructure 494 that is suitable for use with the base connector 422. Theconnection structure 494 is similar to the other connection structuresmentioned previously, and similar or identical features and elementswill not be redundantly described here. For this embodiment, the sensorconductors extend from the infusion tube and are terminated inconductive elastomer plugs 496 located in holes formed in the connectorpins 498.

FIG. 28 is a perspective view of another fluid/electrical connectionstructure 502 that is suitable for use with the base connector 422. Theconnection structure 502 is similar to the other connection structuresmentioned previously, and similar or identical features and elementswill not be redundantly described here. For this embodiment, each sensorconductor extends from the infusion tube and is pressed into aconductive cutter block 504 that extends from the interface component506. The cutter blocks 504 are connected to an interconnect or circuitarrangement of the interface component 506 (not shown in FIG. 26 ),which in turn is electrically coupled to certain features of thesensor-infusion unit.

FIG. 29 is a perspective view of another fluid/electrical connectionstructure 510 that is suitable for use with the base connector 422. Theconnection structure 510 employs three conductive cutter blocks 512 thatcut into the infusion tube 514 to make the electrical connections to thesensor conductors 516 (located inside the infusion tube 514). The cutterblocks 512 are connected to an interconnect or circuit arrangement, orto external wires that can be routed to the sensor-infusion unit. FIG.30 is a partially phantom end view of a portion of the connectionstructure 510, showing how the cutter blocks 512 enter the infusion tube514 to make the connections with the sensor conductors 516.

Modular Embodiment

The embodiments described above include a one-piece combinedsensor-infusion unit that includes both the sensor element and the fluidinfusion element packaged together. Such an integrated implementation isdesirable and appropriate when the expected useful lifespan of thesensor element is approximately the same as the expected useful lifespanof the infusion element (e.g., three days, five days, one week). At thetime of this writing, continuous glucose sensors typically have a longeruseful lifespan than insulin infusion sets. Consequently, a combinedsensor-infusion unit that leverages existing glucose sensor and insulininfusion technology may have a useful lifespan that is limited by thespecifications of the insulin infusion technology. To address thisscenario, alternative embodiments of a combined sensor-infusion unitutilize a modular design having physically distinct sensor and infusionmodules. The modular implementation is described in more detail belowwith reference to FIG. 31 and FIG. 32 .

FIG. 31 is a schematic representation of an exemplary embodiment of amodular sensor-infusion unit 600. The left side of FIG. 31 depicts themodular sensor-infusion unit 600 deployed on the skin 602 of the patientduring an initial period of time (e.g., the first three days of use),and the right side of FIG. 31 depicts the modular sensor-infusion unit600 deployed on the skin 602 during a subsequent period of time (e.g.,the last three days of use). The unit 600 includes a sensor module 604and a compatible infusion module 606. The two modules 604, 606 can beremovably coupled together. This example assumes that the sensor module604 has a useful lifespan rating of six days, and that each infusionmodule 606 has a useful lifespan rating of three days. Accordingly, afirst infusion module 606 a is used for the first three days, and asecond infusion module 606 b is used for the final three days.

The sensor module 604 includes a sensor element 608 intended forinsertion at a sensor site 610 of the patient. The infusion module 606 aincludes a cannula 612 intended for insertion at a first infusion site614 of the patient. The infusion module 606 b includes a cannula 616intended for insertion at a second infusion site 618 of the patient,wherein the second infusion site 618 is different than, and remote from,the first infusion site 614. The initial infusion module 606 a isreplaced with the second infusion module 606 b after three days of use.As depicted in FIG. 31 , the first infusion site 614 is left toheal/recover after removal of the first infusion module 606 a.

The modular design allows either the sensor module 604 or the infusionmodule 606 to by replaced during wear. The sensor and infusion modulesconnect together to form a single on-body assembly. This configurationenables sensors with longer wearable lifespan to be used with infusionsets with shorter wearable time, and provides the versatility to replaceone of the modules only as needed, which in turn reduces the costburden.

The modular design builds on the integrated implementation describedabove, where the sensor electronics assembly is integrated into thecombined unit and has a tethered connection to the infusion devicethrough embedded wires in the infusion set tubing. For this modularimplementation, the sensor electronics can reside in the sensor module,the infusion module, or both. Each module may contain connection pointson each side of the module to allow site rotation.

FIG. 31 depicts an exemplary use case for a six-day wear sensor andthree-day wear infusion sets. On the first day, the sensor and infusionmodules are deployed (inserted) together. On the fourth day, the firstinfusion module 606 a is removed and the second infusion module 606 b isinserted at the opposite side from the previous site, and connected tothe sensor module 604.

The modular design accommodates extended wear times. At the time of thiswriting, the technology for long-term continuous glucose sensors isadvancing quicker than that for insulin infusion sets. Accordingly, thismodular design makes a 14-day combined unit possible. For example: asix-day sensor can be connected with two three-day infusion sets; a14-day sensor can be connected with two seven-day infusion sets; and a12-day sensor can be connected to four 3-day infusion sets.

Sterilization

Sensor and infusion set modules can be sterilized separately based ontheir sterilization compatibility. This reduces the burden of developinga single sterilization platform. In this regard, current sensortechnology is compatible with e-beam sterilization, and infusion setsare compatible with ethylene oxide sterilization. Sensor electronics orcomponents that are incompatible with e-beam sterilization can reside inthe infusion set module for sterilization using ethylene oxide.

Replacement

If either the sensor or infusion set module malfunctions or otherwiserequires maintenance during wear, only the affect module needs to bereplaced without replacing the entire combined assembly.

Interchangeability

Various models of sensors and infusion sets can be connected together.For example: either a 6 mm or 9 mm cannula infusion set module can beconnected with the sensor module; different sensor generations can beconnected to the infusion set module; and upgrades for either the sensoror infusion set module would have minimal impact on the other module,due to the use of a standardized connection.

Insertion/Deployment

In order to simplify replacement of the modules, an insertion device canbe designed to explant and insert new modules as needed. An exemplaryuse case and workflow may be as follows:

Step 1: Load new a sensor or infusion set module into the insertiondevice.

Step 2: Align the insertion device overlying the currently deployedmodular assembly.

Step 3: Operate the insertion device to explant the module that is to bereplaced.

Step 4: Operate the insertion device to insert and attach the new moduleonto the remaining assembly.

FIG. 32 is a simplified block diagram of a connection scheme suitablefor use with a modular sensor-infusion unit of the type described abovewith reference to FIG. 31 . The exemplary embodiment depicted in FIG. 32includes a sensor module 702, an infusion module 704, and a connector706. Some elements, features, and functionality of the modularsensor-infusion unit shown in FIG. 32 are similar or identical to thosedescribed above with reference to FIG. 21 . Accordingly, similar andidentical items will not be redundantly described here.

The illustrated embodiment has the sensor module 702 as the “last inline” component, the infusion module 704 as the “first in line”component, and the connector 706 coupled to the infusion module 704 toprovide the medication fluid and the operating voltage/power to theinfusion module 704. In other embodiments, the positions of the sensormodule 702 and the infusion module 704 can be swapped (with necessarymodifications to the fluid and/or electrical flow paths). A fluid flowpath 710, which leads to the infusion site of the patient, is definedwithin at least the following components: an infusion tube 712; theconnector 706; and the infusion module 704. An electrically conductivepath (which may include any number of conductors, wires, traces, contactpads, or the like), which establishes connectivity between the hostfluid infusion device and the modular sensor-infusion unit, includes oris defined by at least the following components: sensor conductors 714carried by or integrated with the infusion tube 712; a first electricalconnector 716; an electronics assembly 718 of the infusion module 704; asecond electrical connector 720; and an electronics assembly 722 of thesensor module 702. The connectors 716, 720 are similar to the electricalconnector 416 described above, and the electronics assembly 718, 722 aresimilar to the electronics assembly 402 described above (see FIG. 21 ).

The electronics assembly 718 of the infusion module 704 need not includeany active components. In certain embodiments, the electronics assembly718 serves as a pass-through component that only contains conductivetraces, wires, contact pads, and the like, to electrically couple thesensor module 702 to the connector 706. In other embodiments, theelectronics assembly 718 may include some or all of the electronicsrequired to perform analog-to-digital conversion, digital dataconditioning and processing, data transmission, power regulation, etc.

SUMMARY/CONCLUSIONS

The one-piece combined and miniaturized sensor-infusion unit describedabove has an infusion set with an electronic connection to the hostinfusion device. The infusion set eliminates the need for a sensortransmitter, thus significantly reducing the on-body footprint.Electrical signals are routed in or along the infusion set tubing toallow for power and data transmission, eliminating the need for a largebattery and radio frequency circuitry at the sensor base.

A practical goal that is achieved by the combined sensor-infusion unitis to provide an extended wear infusion set (up to seven days, forexample) having a reduced on-body footprint. As an alternate embodiment,a two-part modular sensor-infusion unit has also been presented here. Inaccordance with one example, the modular implementation can be used witha three-day insulin infusion module and a six-day glucose sensor module.The modular embodiment includes two detachable parts, one containing theglucose sensor with the integrated sensor electronics and the otherbeing the infusion set. On day 1, the sensor and infusion set aredeployed and inserted together. On day 4, the first infusion set is beremoved and a new infusion set is inserted at the opposite side from theprevious site and connected to the sensor module. Although the modulardesign requires more complex manufacturing consideration due to thecomplexity of inserting a second infusion set to the pre-existing sensorbase on the body, there will still be a single on-body device. Onepractical goal of this alternative design is to maintain a relativelysmall form factor.

The disclosed embodiments are significantly smaller in size, and consumesignificantly less on-body area than existing products that a separatelyinserted glucose sensor and infusion catheter. Size reduction isachieved by distributing and integrating sensor electronics across thecombined sensor-infusion unit and the host infusion device. Electricalwires can be embedded in the infusion set tubing to allow for power anddata transmission between the combined sensor-infusion unit and theinfusion device, thus eliminating the need for a large battery andwireless communication radio at the combined unit. Minimal electronicsreside at the combined unit to power the sensor and condition thedigital data before sending the data to the infusion device. Withintegrated electronics and wires embedded in the infusion tubing, thecombined unit can be designed and marketed as a disposable device.

The combined sensor-infusion unit incorporates the infusion set cannula,glucose sensor, sensor electronics, and wired tubing connection. Withthe sensor electronics integrated into the combined unit, most of theelements of conventional wireless sensor transmitters can be eliminatedto significantly reduce the device footprint. In this regard, the totalon-body footprint of the one-piece sensor-infusion unit is approximately50% less than separately inserted glucose sensor and insulin infusioncatheters. For example, the on-body area of an exemplary embodiment isabout 1.0 square inch.

A base assembly incorporates the infusion set cannula, glucose sensor,sensor electronics, and wired tubing connection. In order to connectinfusion tube/wires with both a fluid path and electrical elements, anew connection design at the base is provided. The design of thatconnection provides a connection with a minimal overall size.

New glucose sensor and sensor electronics connection schemes can beutilized to minimize size and improve reliability.

An extended wear adhesive patch allows the combined sensor-infusion unitto be be adhered to the body for an extending period, such as sevendays.

A waterproof design for the combined unit and tubing connection can beutilized to prevent damage to the sensor electronics.

A soft cannula can be used for medication delivery. In order to securelyattach the cannula to the base assembly, a suitable cannula hub designcan be leveraged.

The two-purpose connection between the tubing for insulin delivery andelectrical elements should be robustly designed against strain, stress,and liquid leakage while minimizing the form factor and simplifyinginstallation.

A single sterilization method for the glucose sensor, cannula, andsensor electronics can be based on ethylene oxide (EtO) or electron beam(e-beam) technology. Currently, EtO sterilization is used for infusionsets and e-beam sterilization for glucose sensors. In practice, anappropriate sterilization method should be chosen to results in theleast design complexity.

An infusion set tubing with embedded wires as described herein supportsdata and power transmission between the base assembly and the infusiondevice. Conductive wires are placed along the entire length of thetubing. Various methods including co-extrusion processes can be used tointegrate wires into the tubing. It is projected that the tubingmaterial will maintain similar chemical properties (biocompatibility) topreserve insulin integrity. Wire terminations at the tubing ends will bedeveloped for both the base assembly side and the infusion device side.

Signals from the combined sensor-infusion unit will be transmitted tothe infusion device via the wired tubing, which will be connected at oneend to the infusion device. A suitable connector and/or connectionmechanism for the infusion device and tubing set enables reliable signaland power transmission between the components, via the wired tubing.

In certain embodiments, the wired connection to the infusion device iswaterproof such that the system maintains its ingress protection rating(IPX8: 12 feet for 24 hours). The sensor-infusion unit can beimplemented as a consumable device with a service life of about sevendays, while the host infusion device has a design life of more than fouryears. The combination of the above-mentioned requirements provides fora carefully designed electrical connection to the infusion device. Theconnection must withstand four years of multiple connect/disconnectevents, wear-and-tear including multiple drops, scratches, and exposureto water and various chemicals.

The sensor electronics at the base assembly and the infusion device aredesigned to support sensor function and signal transmission. Disposablehardware designs are considered to minimize component costs whilesupporting sensor diagnostics schemes and improvements in sensorreliability. The addition of a battery and memory to the base assemblyenables the continued collection of sensor data in the event of a tubingdisconnection during patient use. Electronics at the infusion deviceside includes hardware to power and communicate with the base assembly.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or embodiments described herein are not intended tolimit the scope, applicability, or configuration of the claimed subjectmatter in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing the described embodiment or embodiments. It should beunderstood that various changes can be made in the function andarrangement of elements without departing from the scope defined by theclaims, which includes known equivalents and foreseeable equivalents atthe time of filing this patent application.

What is claimed is:
 1. A medical device component for delivering medication fluid to a patient, the medical device component comprising: a body-mountable base unit comprising: a base structure; a body-insertable cannula that accommodates delivery of medication fluid to the patient, the cannula having an upstream end securely attached to the base structure and having a downstream end extending from the base structure; a self-sealing septum coupled to the base structure to fluidly seal the upstream end of the cannula; a body-insertable physiological analyte sensor secured to and extending from the base structure, the sensor facilitating measurement of a physiological characteristic of the patient, and the sensor comprising a plurality of sensor leads; and an electronics assembly coupled to the base structure, the electronics assembly electrically connected to the sensor leads to obtain measurements of the physiological characteristic in an analog domain, and the electronics assembly comprising a digital processing circuit to convert measurements of the physiological characteristic from the analog domain into digital sensor data, to digitally process the digital sensor data into conditioned digital sensor data, and to communicate the conditioned digital sensor data to a fluid infusion device associated with the medical device component; and a top cover assembly that is removably couplable to the body-mountable base unit, the top cover assembly comprising: a lid structure that releasably mates with the base structure, the lid structure comprising an interior space defined by an inner surface of the lid structure; an infusion tube secured to the inner surface of the lid structure and terminating within the interior space; a tubing connector fluidly coupled to the infusion tube, the tubing connector having a distal end supported by the lid structure, the distal end of the tubing connector penetrating the self-sealing septum to establish a fluid delivery flow path from inside the infusion tube, through the self-sealing septum, and into the cannula when the top cover assembly is coupled to the body-mountable base unit, wherein the self-sealing septum seals the upstream end of the cannula when the top cover assembly is removed from the body-mountable base unit and the tubing connector is withdrawn from the self-sealing septum; a plurality of sensor conductors carried by or integrated with the infusion tube, the sensor conductors terminating within the interior space; and an electrical interconnect assembly coupled to the inner surface of the lid structure, the electrical interconnect assembly establishing electrical connectivity between the sensor conductors and the electronics assembly when the top cover assembly is coupled to the body-mountable base unit, to facilitate communication of the conditioned digital sensor data from the electronics assembly to the fluid infusion device.
 2. The medical device component of claim 1, wherein: the sensor conductors are embedded in tubing material of the infusion tube; and terminating ends of the sensor conductors extend from an end of the infusion tube, and are exposed for connection to the electrical interconnect assembly.
 3. The medical device component of claim 1, wherein: a first end of the infusion tube is coupled to the inner surface of the lid structure; and the medical device component further comprises a connector assembly coupled to a second end of the infusion tube, the connector assembly being configured to fluidly couple the infusion tube to a fluid reservoir of the fluid infusion device, and to electrically couple the sensor conductors to an electronics module of the fluid infusion device.
 4. The medical device component of claim 1, wherein: the fluid infusion device is an insulin infusion pump; the medical device component is an insulin infusion component; the body-insertable physiological analyte sensor comprises a glucose sensor; and the infusion tube is compatible with insulin medication fluid.
 5. The medical device component of claim 1, the body-mountable base unit further comprising a connector structure for the conditioned digital sensor data, the connector structure mating with electrical contact pads of the electrical interconnect assembly when the top cover assembly is coupled to the body-mountable base unit.
 6. The medical device component of claim 5, wherein: the connector structure comprises conductive elements corresponding to a power conductor, a ground conductor, and a data conductor for communication of the conditioned digital sensor data; and the electrical contact pads of the electrical interconnect assembly physically contact the conductive elements of the connector structure when the top cover assembly is coupled to the body-mountable base unit.
 7. The medical device component of claim 5, the connector structure comprising: a pedestal extending from the body-mountable base unit; and interconnection plugs positioned within the pedestal, the interconnection plugs formed from a conductive elastomeric material, wherein each of the interconnection plugs has a lower end electrically coupled to a corresponding conductive pad of the electronics assembly of the body-mountable base unit.
 8. The medical device component of claim 1, wherein the body-mountable base unit comprises: a top surface; a first hole formed in the top surface, the first hole accommodating the tubing connector, and the first hole accommodating a first insertion needle for inserting the cannula into skin of the patient; and a second hole formed in the top surface, the second hole accommodating a second insertion needle for inserting the physiological analyte sensor into skin of the patient.
 9. The medical device component of claim 1, wherein at least two of the sensor conductors carried by or integrated with the infusion tube provide operating power from the fluid infusion device to the electronics assembly when the top cover assembly is coupled to the body-mountable base unit.
 10. A medical device component for delivering medication fluid to a patient, the medical device component comprising: a fluid infusion device to regulate delivery of medication fluid; a base unit comprising: a base structure; a lid assembly affixed and sealed to the base structure; a cannula that accommodates delivery of medication fluid as controlled by the fluid infusion device, the cannula having an upstream end securely attached to the base structure and having a downstream end extending from the base structure; a self-sealing septum that fluidly seals the upstream end of the cannula, wherein the self-sealing septum is maintained in position between the base structure and the lid assembly; a physiological analyte sensor that facilitates measurement of a physiological characteristic, the sensor comprising a plurality of sensor leads, the physiological analyte sensor secured to and extending from the base unit; and an electronics assembly electrically connected to the sensor leads to obtain measurements of the physiological characteristic in an analog domain, and the electronics assembly comprising a digital processing circuit to convert measurements of the physiological characteristic from the analog domain into digital sensor data, to digitally process the digital sensor data into conditioned digital sensor data, and to communicate the conditioned digital sensor data to the fluid infusion device; and a top cover assembly that is removably couplable to the base unit such that the top cover assembly covers the lid assembly of the base unit, the top cover assembly comprising: a lid structure that releasably mates with the base unit, the lid structure comprising an interior space defined by an inner surface of the lid structure, and the lid structure comprising at least one structural support feature; an infusion tube secured to the inner surface of the lid structure and terminating within the interior space, wherein the at least one structural support feature of the lid structure receives, secures, and retains a downstream end of the infusion tube; a tubing connector fluidly coupled to the infusion tube, the tubing connector having a distal end supported by the at least one structural support feature of the lid structure, the distal end of the tubing connector penetrating the self-sealing septum to establish a fluid delivery flow path from inside the infusion tube to the cannula when the top cover assembly is coupled to the base unit; a plurality of sensor conductors terminating within the interior space; and an electrical interconnect assembly coupled to the inner surface of the lid structure, the electrical interconnect assembly establishing electrical connectivity between the sensor conductors and the electronics assembly when the top cover assembly is coupled to the base unit, to facilitate communication of the conditioned digital sensor data from the electronics assembly to the fluid infusion device.
 11. The medical device component of claim 10, wherein: the sensor conductors are carried by or integrated with the infusion tube; and terminating ends of the sensor conductors extend from an end of the infusion tube, and are exposed for connection to the electrical interconnect assembly.
 12. The medical device component of claim 10, wherein: the medical device component further comprises a connector assembly coupled to a second end of the infusion tube, the connector assembly being configured to fluidly couple the infusion tube to a fluid reservoir of the fluid infusion device, and to electrically couple the sensor conductors to an electronics module of the fluid infusion device.
 13. The medical device component of claim 10, the base unit further comprising a connector structure for the conditioned digital sensor data, the connector structure mating with electrical contact pads of the electrical interconnect assembly when the top cover assembly is coupled to the base unit.
 14. The medical device component of claim 10, wherein the base unit comprises: a top surface; a first hole formed in the top surface, the first hole accommodating the tubing connector, and the first hole accommodating a first insertion needle for inserting the cannula into skin of the patient; and a second hole formed in the top surface, the second hole accommodating a second insertion needle for inserting the physiological analyte sensor into skin of the patient.
 15. The medical device component of claim 10, wherein at least two of the sensor conductors provide operating power from the fluid infusion device to the electronics assembly when the top cover assembly is coupled to the base unit.
 16. A medical device component for delivering medication fluid to a patient, the medical device component comprising: a body-mountable base unit comprising: a base structure; a lid assembly affixed and sealed to the base structure; a body-insertable cannula that accommodates delivery of medication fluid to the patient, the cannula having an upstream end securely attached to the base structure and having a downstream end extending from the base structure; a self-sealing septum coupled to the base structure to fluidly seal the upstream end of the cannula, wherein the self-sealing septum is maintained in position between the base structure and the lid assembly; a body-insertable physiological analyte sensor secured to and extending from the base structure, the sensor facilitating measurement of a physiological characteristic of the patient, and the sensor comprising a plurality of sensor leads; and an electronics assembly coupled to the base structure, the electronics assembly electrically connected to the sensor leads; and a top cover assembly that is removably couplable to the body-mountable base unit such that the top cover assembly covers the lid assembly of the body-mountable base unit, the top cover assembly comprising: a lid structure that releasably mates with the base structure, the lid structure comprising an interior space defined by an inner surface of the lid structure, and the lid structure comprising at least one structural support feature; an infusion tube secured to the inner surface of the lid structure and terminating within the interior space, wherein the at least one structural support feature of the lid structure receives, secures, and retains a downstream end of the infusion tube; a tubing connector fluidly coupled to the infusion tube, the tubing connector having a distal end supported by the at least one structural support feature of the lid structure, the distal end of the tubing connector penetrating the self-sealing septum to establish a fluid delivery flow path from inside the infusion tube, through the self-sealing septum, and into the cannula when the top cover assembly is coupled to the body-mountable base unit, wherein the self-sealing septum seals the upstream end of the cannula when the tubing connector is withdrawn from the self-sealing septum; a plurality of sensor conductors carried by or integrated with the infusion tube, the sensor conductors terminating within the interior space; and an electrical interconnect assembly coupled to the lid structure, the electrical interconnect assembly establishing electrical connectivity between the sensor conductors and the electronics assembly when the top cover assembly is coupled to the body-mountable base unit.
 17. The medical device component of claim 16, wherein: the electronics assembly obtains measurements of the physiological characteristic in an analog domain; and the electronics assembly comprises a digital processing circuit to convert measurements of the physiological characteristic from the analog domain into digital sensor data, to digitally process the digital sensor data into conditioned digital sensor data, and to communicate the conditioned digital sensor data to a fluid infusion device associated with the medical device component.
 18. The medical device component of claim 17, the body-mountable base unit further comprising a connector structure for the conditioned digital sensor data, the connector structure mating with electrical contact pads of the electrical interconnect assembly when the top cover assembly is coupled to the body-mountable base unit.
 19. The medical device component of claim 16, wherein: the sensor conductors are embedded in tubing material of the infusion tube; and terminating ends of the sensor conductors extend from an end of the infusion tube, and are exposed for connection to the electrical interconnect assembly.
 20. The medical device component of claim 16, wherein at least two of the sensor conductors carried by or integrated with the infusion tube provide operating power from the fluid infusion device to the electronics assembly when the top cover assembly is coupled to the body-mountable base unit. 